Study on the emulsion-breaking performance of cross-linked polyether demulsifiers for the emulsion produced by surfactant/polymer flooding in Shengli oilfield
In view of the difficulties in breaking the emulsion produced by surfactant/polymer flooding in Shengli oilfield,the cross-linked polyether demulsifiers D-BP,D-TA and D-PA were prepared by cross-linking polyether demulsifiers with dewatering function for water-in-oil(W/O)emulsion and polyether demulsifier with oil-removal function for oil-in-water(O/W)emulsion.The interfacial activities of the three cross-linked polyether demulsifiers were investigated.Their effects on the oil-water interfacial film of emulsions were examined,and their emulsion-breaking effects on W/O and O/W emulsions were explored.The results showed that among the three cross-linked polyether demulsifiers,D-PA with hyperbranched structure had the strongest adsorption at the oil-water interface and showed the highest interfacial activity.D-PA had the greatest effect on the oil-water interfacial film formed by the kerosene-diluted crude oil and produced water.The new film formed after D-PA adsorption at the oil-water interface had the lowest interfacial dilatational modulus.The dewatering rate of W/O emulsion by D-PA was 94.4%,and the oil removal rate for O/W emulsion from the same oilfield reached 98.1%.More importantly,the D-PA demulsifier was capable of simultaneously treating complex emulsions containing W/O and O/W types.The comprehensive dewatering rate by D-PA for the emulsion produced by surfactant/polymer flooding containing W/O and O/W was above 98%,and the oil content of the effluent after treated was less than 30 mg/L.The retention rate of polymer(HPAM)reached 94.8%,and the oil-water interface was neat and without emulsified intermediate layer.
produced liquid of surfactant/polymer floodingcross-linked polyether demulsifieremulsion breakingpolymer
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